Redescription of Rhabdochona (Rhabdochona) acuminata (Nematoda: habdochonidae) from freshwater fishes from Patagonia (Argentina), the geographical implications

Abstract

Rhabdochona (Rhabdochona) acuminata is redescribed from specimens parasitizing Diplomystes mesembrinus (Siluriformes: Diplomystidae) and Percichthys trucha (Perciformes: Percichthyidae) from the Chubut River, Patagonia, Argentina. The present report is the first record of this nematode in D. mesembrinus; it also confirms P. trucha as host and Patagonia as a region of distribution for R. (R.) acuminata. Morphological features of the species were described using light and scanning electron microscopy. Compared with previous descriptions from Brazil, a very similar morphology is observed. However, a large morphometric variability is found, mainly in body size, spicule ratio, and number and arrangement of pre- and postcloacal papillae.